Atmel ATmega328P Xplained Mini MEGA328P-XMINI MEGA328P-XMINI Data Sheet
Product codes
MEGA328P-XMINI
22
ATmega48A/PA/88A/PA/168A/PA/328/P [DATASHEET]
Atmel-8271H-AVR- ATmega-Datasheet_08/2014
8.6
Register Description
8.6.1
EEARH and EEARL – The EEPROM Address Register
• Bits [15:10] – Reserved
These bits are reserved bits in the ATmega48A/PA/88A/PA/168A/PA/328/P and will always read as zero.
• Bits 9:0 – EEAR[9:0]: EEPROM Address
The EEPROM Address Registers – EEARH and EEARL specify the EEPROM address in the
256/512/512/1Kbytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and
255/511/511/1023. The initial value of EEAR is undefined. A proper value must be written before the EEPROM
may be accessed.
256/512/512/1Kbytes EEPROM space. The EEPROM data bytes are addressed linearly between 0 and
255/511/511/1023. The initial value of EEAR is undefined. A proper value must be written before the EEPROM
may be accessed.
Note:
1.
EEAR9 and EEAR8 are unused bits in ATmega 48A/48PA and must always be written to zero.
8.6.2
EEDR – The EEPROM Data Register
• Bits 7:0 – EEDR[7:0]: EEPROM Data
For the EEPROM write operation, the EEDR Register contains the data to be written to the EEPROM in the
address given by the EEAR Register. For the EEPROM read operation, the EEDR contains the data read out
from the EEPROM at the address given by EEAR.
address given by the EEAR Register. For the EEPROM read operation, the EEDR contains the data read out
from the EEPROM at the address given by EEAR.
8.6.3
EECR – The EEPROM Control Register
• Bits 7:6 – Reserved
These bits are reserved bits in the ATmega48A/PA/88A/PA/168A/PA/328/P and will always read as zero.
• Bits 5, 4 – EEPM1 and EEPM0: EEPROM Programming Mode Bits
The EEPROM Programming mode bit setting defines which programming action that will be triggered when
writing EEPE. It is possible to program data in one atomic operation (erase the old value and program the new
value) or to split the Erase and Write operations in two different operations. The Programming times for the
different modes are shown in
writing EEPE. It is possible to program data in one atomic operation (erase the old value and program the new
value) or to split the Erase and Write operations in two different operations. The Programming times for the
different modes are shown in
. While EEPE is set, any write to EEPMn will be ignored. During reset,
the EEPMn bits will be reset to 0b00 unless the EEPROM is busy programming.
Bit
15
14
13
12
11
10
9
8
–
–
–
–
–
–
EEAR9
EEAR8
EEARH
EEAR7
EEAR6
EEAR5
EEAR4
EEAR3
EEAR2
EEAR1
EEAR0
EEARL
7
6
5
4
3
2
1
0
Read/Write
R
R
R
R
R
R
R
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
X
X
X
X
X
X
X
X
X
Bit
7
6
5
4
3
2
1
0
MSB
LSB
EEDR
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
Bit
7
6
5
4
3
2
1
0
–
–
EEPM1
EEPM0
EERIE
EEMPE
EEPE
EERE
EECR
Read/Write
R
R
R/W
R/W
R/W
R/W
R/W
R/W
Initial Value
0
0
X
X
0
0
X
0